JPS6244934A - Magnetron device - Google Patents

Abstract

PURPOSE:To obtain a magnetron device suitable for mass production while requiring no screw stopping by forming a frame yoke from single metal band folded in right angle at four points in longitudinal direction then arranging such that the opposite end sections in longitudinal direction of said metal band will face each other approximately in the center on the outer endface of annular permanent magnet. CONSTITUTION:U-shaped yoke 18 for magnetically coupling the other magnetic poles of first and second annular permanent magnets 5, 6 is made of single metal band folded in right angle at two points in longitudinal direction. Second annular permanent magnet 6 is stacked through an auxiliary yoke board 16 onto the bottom face of U-shaped yoke 18 then the anode section of magnetron 1 and first annular permanent magnet 5 are stacked sequentially in this order. A through-hole 19 for inserting the electromagnetic wave discharge terminal 15 of magnetron 1 is made through the bottom face section of U-shaped yoke 18 while a groove 20 is made in the folding section at the opposite sideface sections and semi-circular notches 21 are made at the opposite end sections in longitudinal direction. The height of said groove 20 is matched with the height of the top face of first annular permanent magnet 5.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetron device comprising a magnetron and its excitation circuit member, and particularly to a magnetron device suitable for use in a microwave oven.

BACKGROUND ART 14' A magnetron device used in a microwave oven or the like is constructed as shown in FIG. A second magnetic pole piece 4 is provided at the other open end. In addition, the first annular permanent magnet 6 coaxially provided on the outer end surface of the first magnetic pole piece 3 magnetically couples one magnetic pole N to the first magnetic pole piece 3, and A second annular permanent magnet 6 coaxially provided on the outer end surface of the magnetic pole piece 4 magnetically couples one magnetic pole S to the second magnetic pole piece 4 . A frame-shaped yoke 7 for magnetically coupling the other magnetic poles of the first and second annular permanent magnets 6 and 6 is connected to a first yoke member 8 having a U-shaped cross section, and a first yoke member 8 having a U-shaped cross section. It has a cross-sectional shape in which a second yoke member 9 of the shape is integrally connected with screws 3 and screws 10, and surrounds the anode cylinder 2 and the first and second annular permanent magnets 5, 6, etc. are doing.

A large number of radiation fins 11 are attached in multiple stages to the outer peripheral surface of the anode cylinder 2, and a metal shield case 12 is screwed onto the outer end surface of the first yoke member 8. Or it is attached with rivets, etc. Then, the cathode terminal lead-out stem portion 13 protruding from the first magnetic pole piece 3 passes through the through hole 14 of the first yoke member 8 to the shield case 12.
An electromagnetic wave emitting terminal 15 that is inserted into the second magnetic pole piece 4 and protrudes from the second magnetic pole piece 4 projects through the through hole of the second yoke member 9 . Reference numeral 16 indicates an auxiliary yoke plate, and reference numeral 17 indicates an annular gasket made of a braided body of thin metal wires.

Problems to be Solved by the Invention In the conventional magnetron device configured as described above, when forming the frame-shaped yoke 7, the first and second yoke members 8 and 9 are at least screwed together by screws 10. It is necessary to connect the parts at four points, which requires cumbersome thread cutting and screw tightening work, which is one of the factors that hinders the efficiency of device manufacturing.

Therefore, it is an object of the present invention to provide a magnetehedron device that does not require screw fixing as described above and is suitable for mass production.

According to the present invention, a frame-shaped yoke is formed by a single strip-shaped metal plate bent at right angles at four points along its length. Both longitudinal ends of this strip-shaped metal plate are configured to face each other approximately at the center of the outer end surface of the annular permanent magnet.

Function: With this configuration, not only does it become unnecessary to assemble the frame-shaped yoke by tightening screws, but the materials used can also be reduced.
It becomes possible to efficiently manufacture a low-cost frame-shaped yoke by simple bending.

Embodiment As shown in FIG. 1, the anode tube 5 of the magnetron 1 has a first magnetic pole piece 3 at one open end and a second magnetic pole piece 4 at the other open end. However, one magnetic pole of the first annular permanent magnet 5 coaxially provided on the outer end surface of the first magnetic pole piece 3 is connected to the first magnetic pole piece 3 and on the outer end surface of the second magnetic pole piece 4. The point that one magnetic pole of the second annular permanent magnet 6 provided coaxially with the second magnetic pole piece 4 is magnetically coupled to the second magnetic pole piece 4 is the same as before.

However, the U-shaped yokes 18 for magnetically coupling the other magnetic poles of the first and second annular permanent magnets 5 and 6 are located at two locations in the length direction, as shown in FIG. Consists of a single strip of metal bent at right angles. A second annular permanent magnet 6 is mounted on the bottom of this U-shaped yoke 18 on the auxiliary yoke plate 1.
6, and the anode part of the magnetron 1 and the first annular permanent magnet 6 are sequentially stacked thereon.

The bottom of the U-shaped yoke 18 is provided with a through hole 19 through which the electromagnetic wave emitting terminal 15 of the magnetron 1 is inserted. , semicircular notches 21 are provided at both ends in the length direction. However, the height occupied by the groove 2o is matched to the height occupied by the top surface of the first annular permanent magnet 5.

In the assembled state shown in FIG. 1, both sides of the radiation fins 11 attached in multiple stages to the outer peripheral surface of the anode cylinder body 2 are in contact with both sides of the U-shaped yoke 18, so that the magnetron 1. The first and second annular permanent magnets 5, 6 and the U-shaped yoke 18 can maintain a predetermined relative position. In this assembled state, when both side surfaces of the U-shaped yoke 18 are bent inward at right angles at the grooves 2o, both ends thereof are placed above the outer end surface of the annular permanent magnet 5 as shown in FIG. The U-shaped yoke transforms into a frame-shaped yoke, and the circular hole formed by the two semicircular notches 21 becomes a through hole for the stem 13 for leading out the cathode terminal of the magnetron 1. It becomes a hole.

The abutment of both lengthwise ends of the yoke 18 can be made with a joint structure as shown in FIG. 4 or FIG. Since it is located approximately at the center on the outer end surface of the magnet 6, the influence of magnetic resistance here on the excitation circuit is small. Furthermore, by forming the shield case 12 from a magnetic metal, the magnetic resistance can be eliminated. Furthermore, deformation due to widening of the gap at the abutting portion of the frame-shaped yoke can be prevented by fixing the shield case 12 to the frame-shaped yoke at multiple locations with screws, rivets, or welding. .

Effects of the Invention Since the present invention is configured as described above, there is no need for troublesome screw-tightening work or thread-cutting process to assemble the frame-shaped yoke, and there is no need to overlap yoke members at the screw-fastened portion. Therefore, it is possible to reduce the manufacturing cost and the weight of the device, and it is possible to obtain a highly efficient magnetron device suitable for mass production.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view of a magnetron device embodying the present invention in the assembly process, Fig. 2 is a perspective view of a U-shaped yoke of the same device, and Fig. 3 is a partially cutaway side view of the same device after assembly is completed. , FIG. 4 and FIG. 6 are side views of essential parts in other embodiments of the present invention, and FIG. 6 is a partially cutaway side view of a conventional magnetron device. 1... Magnetron, 2... Anode cylinder, 3, 4... Magnetic pole piece, 6, 6... Annular permanent magnet, 18... ...U-shaped yoke. Name of agent: Patent attorney Toshio Nakao and 1 other person 1B
-, + Cane Lin Scissors Figure 2 Figure 3 Figure 4 Figure 1 C Figure 5 @ Figure 6

Claims (1)

[Claims] A magnetron having a first magnetic pole piece at one open end of an anode cylinder and a second magnetic pole piece at the other open end, and coaxially provided on the outer end surface of the first magnetic pole piece. a first annular permanent magnet having one magnetic pole magnetically coupled to the first magnetic pole piece; A second annular permanent magnet having one magnetic pole magnetically coupled to the anode cylindrical body and the first and a frame-shaped yoke surrounding a second annular permanent magnet; the frame-shaped yoke is made of a single strip-shaped metal plate bent at right angles at four points in the length direction; A magnetron device characterized in that both end portions face each other approximately at the center of the outer end surface of the first annular permanent magnet.